RT Journal Article T1 Sun, heat and electricity. A comprehensive study of non-pollutant alternatives to produce green hydrogen A1 Caparrós Mancera, Julio José A1 Segura Manzano, Francisca A1 Andújar Márquez, José Manuel A1 López González, Eduardo A1 Isorna Llerena, Fernando AB Water-based hydrogen production is currently an attractive research field, as it provides a greener method to produce hydrogen than existing alternatives. Green hydrogen is expected to progressively replace fossil fuels, which are highly harmful environmentally. This paper presents a critical analysis over time of the main water splitting technologies currently in use for sustainable hydrogen production. As a result of the critical analysis, all the studied techniques have been ordered chronologically in the way that it is possible to understand how new materials have driven to new techniques, more efficient and less expensive. This allows having a complete vision of these technologies. A high level of maturity has been reached in electrolysis, while other techniques still have a long way to go, although many improvements and relevant advancements have been made over the years. The paper offers a global and comparative vision of each technology. From this, it is possible to identify the different paths where efforts are needed to make water-based hydrogen production a mature, stable and efficient technology. PB Wiley SN 0363-907X SN 1099-114X (electrónico) YR 2022 FD 2022-08-10 LK https://hdl.handle.net/10272/21410 UL https://hdl.handle.net/10272/21410 LA eng NO Caparrós Mancera, J. J., Segura Manzano, F., Andújar, J. M., López, E., & Isorna, F. (2022). Sun, heat and electricity. A comprehensive study of non‐pollutant alternatives to produce green hydrogen. International Journal of Energy Research, 46(13), 17999–18028. https://doi.org/10.1002/er.8505 NO This work is a contribution of the following Projects: “H2Integration&Control. Integration and Control of a hydrogen-based pilot plant in residential applications for energy supply”, Ref. PID2020-116616RB-C31 supported by the Spanish State Program of R + D + I Oriented to the Challenges of Society; “Saltes. Smartgrid with reconfigurable Architecture for testing control Techniques and Energy Storage priority”, Ref. P20-00730 supported by Regional Andalusian Government, under the European Union Regional Development Fund; and the project “G2GH2-Going to Green Hydrogen. High efficiency and low degradation system for the hydrogen production without contaminant waste”, Ref. UHU-1259316 supported by the European Union Regional Development Fund 2014/2020. Funding for Open Access charge: University of Huelva (UHU) / CBUA. DS Repositorio Institucional de la Universidad de Huelva RD 30 may 2026